Yasin Hassan Omar arrived in Britain from Somalia in 1992 at age 11, the Home Office said. The 24-year-old, a Somali citizen with British residency, is suspected of attempting to blow up a subway train near Warren Street station.
Mukhtar Said Ibrahim, 27, also known as Mukhtar Muhammad Said, came to Britain in 1990, his family said. He was granted residency in 1992 and British citizenship in September 2004, the Home Office said.
Both are the children of refugees, the government said.
Said attended his local north London high school in the Stanmore neighbourhood between 1991 and 1994, when his family said he moved away from home, returning only rarely to visit.
"We were shocked when we saw Mukhtar's picture in the national news," the family said in a statement. "We immediately attended the police station and made statements to the police. We would suggest that anyone with information contacts the police."
Neighbour Sarah Scott remembered a discussion with Said in November about religion, and his reaction when she told him she was an atheist.
"He said I should (believe in God) and that he was going to get me some information," the 23-year-old said. He returned with a booklet called "Understanding Islam," in which he had highlighted key passages.
A British police forensic expert
stands near a police tent
"Anyone who says, 'There is no God except Allah' and dies holding to that will enter paradise," she recalled one passage as reading.
She said he had never talked about terrorism but did express his general disgust with society.
"He talked about evil spirits. He said there were a lot of evil sprits around because everyone was evil around here," she said.
Police were trying to determine whether the failed 21 July bombings were connected to the deadly 7 July attacks that killed 52 people and the four bombers.
On Tuesday, police explosives experts were examining what they called suspicious material found in a search of Omar's apartment. Said had recently visited the apartment, according to Peter Clarke, head of the Metropolitan Police anti-terrorist squad.
"We are taking things away from the apartment, but we have not yet done analysis on what it is," a police spokeswoman said on customary condition of anonymity.
They also impounded a white Volkswagen Golf near the apartment in connection with their investigation of the 21 July bombing attempts, the spokeswoman said.
"We checked the car to see if there were any explosives on it and there were not, but we took it away for further forensic examination," she said.
Police have been searching Omar's apartment in a concrete high-rise since raiding it late Monday.
"We were shocked when we saw Mukhtar's picture in the national news"
A spokeswoman for the London borough, the Enfield Council, told The Associated Press that Omar had been the registered tenant in the apartment since 1999, receiving 75 pounds a month in government housing benefits until May.
Police also were questioning five people arrested in connection with the 21 July attacks.
The bombs, which failed to fully detonate, were stored in clear plastic food containers and put into dark-coloured bags or backpacks. Clarke said those four bombs were similar to another found abandoned in a park Saturday, raising fears that a fifth bomber is on the loose.